In the field of fabricating integrated circuits on insulating substrates, such as SIMOX, bonded wafers and the like, there has been a constant problem of forming a body contact.
As is well known, MOS transistors need a body contact to avoid charge buildup within the body.
Many schemes have been devised to form a body contact during the process of transistor formation. These schemes take away area from the active area of the transistor.
Other schemes have been devised to form body contacts at an early stage—e.g. before the bonding of the two wafers. Such schemes not only have an obvious problem with alignment, they commit the wafer to a particular circuit layout that places the transistors in a fixed position.